686658623 has 8 divisors (see below), whose sum is σ = 784918560. Its totient is φ = 588440160.

The previous prime is 686658601. The next prime is 686658631. The reversal of 686658623 is 326856686.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 686658623 - 2⁶ = 686658559 is a prime.

It is a super-2 number, since 2×686658623² = 943000129080512258, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686658653) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44453 + ... + 57873.

It is an arithmetic number, because the mean of its divisors is an integer number (98114820).

Almost surely, 2^686658623 is an apocalyptic number.

686658623 is a deficient number, since it is larger than the sum of its proper divisors (98259937).

686658623 is a wasteful number, since it uses less digits than its factorization.

686658623 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20737.

The product of its digits is 2488320, while the sum is 50.

The square root of 686658623 is about 26204.1718625107. The cubic root of 686658623 is about 882.2268939596.

The spelling of 686658623 in words is "six hundred eighty-six million, six hundred fifty-eight thousand, six hundred twenty-three".